Wire or line clamp



April 2, 1957 c. G. SORFLATEN ET AL 2,737,775

WIRE OR LINE CLAMP Filed Feb. 5, 1954 FIG. I

I3 I i l2 INVENTORS.

- 1 CHESTER e. SORFLATEN GEORGE R. WHITESIDE ATTORNEY WIRE OR LINE CLAMPChester G. Sorflaten, Chicago, and George R. Whiteside, Wilmington, 111.

Application February 5, 1954, Serial No. 498,381

2 Claims. (Cl. 339265) This invention relates in general to wire or lineclamps and more specifically to a new and improved type of multiplepurpose clamp particularly suited for either clamping two or moreconductors under high pressure to provide an excellent low resistanceelectrical connection, or to terminate a tensioned overhead line such asa distribution conductor by clamping the end of the conductor to itselfafter said end has been looped thru a thimble or other suitableinsulator provided for such terminating purposes.

The primary object of this invention is to provide a highly eflicientand durable clamp of the type described which is suitable for makingexcellent low resistance electrical connections between conductors,especially overhead and either of the same size or of difierent sizes aswell as for terminating various sizes of distribution conductors. Thisobject is attained by virtue of the high pressure which the clamp iscapable of developing and the highly desirable feature due to closelyfitting conductor grooves of suitable length to distribute the pressureevenly to the portion of the conductor or conductors subject to theclamp, whether said conductors be of the single or multiple strandvariety.

Another object is to provide a clamp that can be applied with simplehand tools such as adjustable end wrenches or open end wrenches and yetdevelop an extremely high pressure by the arrangement of its parts in amanner most efficient. I

Another object of this invention in keeping with the foregoing is toprovide a clamp especially valuable and for most advantageous use withaluminum conductors.

Still another object of this invention is to provide a clamp suitablefor a wide range of conductor sizes with out sacrificing the feature ofa uniformly close fitting wire groove.

Yet another object is to provide a clamp the application of which may beachieved with ease by furnishing an assembly of parts which need not bedisassembled or disassociated for application to the conductors.

An outstanding feature of this invention resides in its adaptability tomanufacture of all the parts thereof from a given metal compatible withthe composition of the conductor.

These and other objects and advantages will become more readily apparentas the following description proceeds taken in conjunction with theaccompanying sheet of drawings illustrating a preferred embodiment ofthis invention.

In the drawings:

Fig. l is an exploded view of a clamp according to the present inventionhaving only a single intermediate engaging member or bar so as toaccommodate only two conductors or the looped end of a single conductor.

Fig. 2 is an elevational view of the clamp of Fig. 1, in assembled openposition ready for application.

Fig. 3 is a top plan view of the clamp of either Fig. 2 or 4.

nited States Patent Fig. 4 is an elevational view of a clamp such asshown in the previous figures but modified to the extent of beingprovided with a plurality of intermediate engaging members and adaptedto clamp and connect a plurality of wires of different sizes. The clampof this figure is shown in closed or operative position.

Referring now more particularly to the drawings and Fig. 1, a basicmember 10 comprises an elongate central section having a groove 11preferably of semi circular cross section extending the length thereof.The groove 11 provides a wire or line bearing surface to closely embracea conductor. Midway between the ends of the central section of the basicmember 10 and integrally attached to either side are bosses 12 and 13.Openings 14 in each of the bosses 12 and 13 provide slidable entrancefor bolts 15 and 16, the heads 17 and 18 of which bear against theoutside of the bosses 12 and 13 to exert a pressure against the basicmember 10 for clamping the several parts together as will be explainedhereinafter. Integrally attached to sides of the boss 13 and on oppositesides of the opening 14 therein are two parallel guides or rails 19extending upwardly and at right angles to the plane of the inside of thebasic member 10. These guides 19 serve to insure alignment of and toretain the several parts of the device in proper relationship orattitude one to another as well as to provide for relative slidingmovement of the parts toward and away from the basic member 10, as willbe described more fully subsequently.

A cap member 20 comprises a central section correspondingly elongatewith that of the basic member ill and having a wire bearing groove 21preferably of semi circular cross section extending the length of thesection to receive a conductor. On either side of the central section ofthe cap member 26 at its midpoint and integrally attached thereto arebosses 22 and 23 which have threaded openings 24 and 25 to threadablyreceive the bolts 15 and 16 respectively. The boss 23 may be providedwith an extension 26 extending downwardly toward the basic member 10 andbetween the guides 1s. The extension 26 permits the clamp assembly to beopened to a greater extent without disengaging the bolt 18 which inoperation is prethreaded partially into the cap member 20, and it formsan extension to the guiding surfaces 27 on each side of the boss 23which operate between the two guides 19. This arrangement maintains thecap member 20 in alignment while permitting relative move ment slidablytoward and away from the basic member 10. Grooves 28 and projections 29on each side of the boss 23 (see Fig. 3) retain the boss and itsextension 26 between the guides 19 while permitting slidable movement ofthe cap member 20 relative thereto.

Interposed between the basic member 10 and the cap member 20 there is anengaging or spacer bar member 30. Alignment of the bar member 30 withrespect to the other members is achieved by means of the guides 19attached to the basic member 10 and a rectangular opening formed in thebar member 30 by two arms 32 integrally attached thereto and facingprojections 31 on the ends of said arms. The rectangular opening thusformed in the bar member 30 achieves alignment by closely embracing therectangle formed by the two guides 19 and there- 'by prevents rotationand restricts movement toward and tors or the looped end of a conductor.It is to be noted that the curvatures of the registering groovescorrespond and altho in this illustration they have been shown to all beidentical to meet the condition of terminating the looped end of asingle conductor, the registering grooves of one pair need notcorrespond to the registering grooves of the other pair as would be thecase if two wires of different size were being connected.

A retaining means in the form of a washer 35 of a resilient materialsuch as Neoprene snugly fits the bolt and prevents disengagement of thatbolt from the basic member while the conductors are being positioned inthe respective pairs of grooves. The various parts likewise cannotbecome misaligned during this phase of an operation.

After the conductors have been located in their respective pairs ofgrooves, the bolt 15 is threaded into the threaded hole 24 in the capmember and both bolts 15 and 16 are then manipulated until both aredrawn tight whereupon the clamp'is complete and the conductor orconductors are secured therein.

it should be noted here that the ends of the wire bearing grooves arepreferably smoothly rounded as at 36 so that no scoring of the conductorby the, edges of the grooves can occur either as the pressure is appliedor from moveient of the conductors themselves relative to the clamp suchas might be occasioned by line sway or flexing caused by the elements.

In Fig. 4 there is illustrated a clamp which in all respects issubstantially the same as the clamp previously described with theexception that a plurality. of intermediate bar members have beenprovided. These are indicated by reference characters 39a and 36b. Thetwo facing grooves 37 and 38 of the bar members 30a and 3% areillustrated as being of corresponding but smaller curvature than thefacing grooves 11 and 33a and 21 and 34a which respectively correspondin size as might be expected for use in connecting a smallerdistribution line or drop with larger distribution lines. The clamp inFig. 4 is moreover shown in closed or operative position with wires orlines 39, 40 and 41 securely clamped and connected mechanically andelectrically between the various members of the assembly.

From the foregoing description it. should be apparent that numerousadvantages are gained in a clamp made in accordance with the principlesof this invention. The arrangement of bolts, one on each side of theconductor and operating thru the especially formed clamp parts has beenfound to be the most efiicient means for balancing the applied pressuregiving a total pressure to the conductors equal to the sum of thepressures developed by each of the bolts. The rotational forces are alsobalanced by this arrangement so that no stress is set. up in the guidesthereby eliminating any binding action between the parts. The mostadvantageous amount of torque capable of being applied by hand wrenchesis achieved by preferably providing the bolts with threads of theAmerican Fine Thread Series.

It has also been found that a clamp such as provided by this inventionis particularly desirable for use with aluminum conductors because of anever present oxide film on the surface of such conductors which is avery poor electrical conductor and which unless removed can seriouslyaffect the conductivity of the conductor. By providing a clamping meanscapable of exerting extremely high pressure evenly, the strands of analuminum conductor are sufficiently distorted to disassociate the oxidefilm from the contact surfaces and thus provide an excellent electricalconnection of negligible resistance. Heretofore known connectors requirethe conductor strands to be wire brushed with a special greaselikecompound, to first scratch the surface and to cover it immediately toprevent reoxidation. The high pressure developed by this clamp isfurther desirable for terminating or dead-ending tensioned overheadconductors of aluminum. The efficiency of a clamp for dead endingdepends on the amount of surface contact area that the clampcan developwith the strands of the conductor, By virtue. qf.the novelconcept 4 ofthe instant clamp, high pressure is distributed equally over a maximumof contact area.

The shape requirements of the grooves for the multiple purposes uses ofthis clamp as noted have been found to be complementary, that is a shapethat equally distributes a. generous amount of contact area among asmany strands of the conductor as possible has been discovered to be acriterion for both good conductivity as well as efiicient holding power.

it should be noted as a distinct advantage that all parts of this clampare interchangeable and by providing bar members with differentcurvatures in the grooves on either side, any combination of wire sizesmay be efficiently clamped together.

Ry provision of guides integral with one of the members and associatedwith all the other parts, alignment and slidabie movement is achieved sothat easy entrance of the conductors to be clamped is afforded as wellas the ability to apply the pressure to the members and the conductorswithout disassembly of the parts. This is particularly advantageous whenapplying the clamp to high voltage lines where hot-line tools are used.

Moreover the clamp may be made of almost any suitable metal or alloy andwhich can be chosen to correspond to the properties of the conductors toobviate ditficulties encountered due to different ratcs of thermalexpansion of metals of diifering properties, so that good highconductivity connections can be maintained notwithstanding the severetemperature cycles which are encountered on overhead systems or highlines.

it will be apparent therefore that the clamp described is capable ofserving multiple purposes to great advantage. It should also beunderstood that altho only a preferred embodiment has been described,such modifications as will be suggested to those skilled in the art andcoming within the spirit of the invention are intended as being withinits scope as best defined by the appended claims.

We claim:

1. A line clamp comprising outer rigid metallic members non-rotatablewith respect to one another yet relatively movable toward and away fromeach other and each being provided with a line bearing groove, at leastone additional rigid metallic member intermediate said outer members,relatively movable toward and away therefrom and provided with linebearing grooves in opposite surfaces respectively in register with thecorresponding rooves in the adjacent members, means including at leastone elongate guide rail integrally connected to one of the outer memberscentrally and to one side only thereof cxtending substantially the fullheight of the clamp adapted to maintain in register the line bearinggrooves of all of said members at all times in said relative movementand to permit insertion of conductors into said registering line bearinggrooves fromthe side opposite said guide rail, and means disposed onopposite sides of said line bearing grooves in the members for exertinga high pressure to draw said members together to tightly grip linesdisposed in the registering pairs of grooves and to maintain them soclamped under high pressure.

2. A line clamp comprising outer rigid metallic members non-rotatablewith respect to one another yet relatively movable toward and away fromeach other and each being provided with a line bearing groove, at leastone additional rigid metallic member intermediate said outer membersrelatively movable toward and away therefrom and provided with linebearing grooves in opposite surfaces respectively in register with thecorresponding grooves in the adjacent members, means including a pair ofparallel elongate guide rails integrally connected to one of the outermembers centrally and to one side only thereof extending substantiallythe. full height ofthe clamp adapted to maintain in register the linebearing grooves of all of said members at all times in said relativemovement and to permit insertion of conductors into said registeringline bearing grooves from the side opposite said pair of guide rails,bosses centrally disposed on opposite sides of said line bearing groovesin the outer members, and means comprising a pair of bolts slidablyextending thru the bosses in one of the outer members and threadedlyextending into the bosses of the other one of 5 the outer members.

References Cited in the file of this patent UNITED STATES PATENTS GroverJune 26, 1934 10 Lee Mar. 10, 1936 Bergan Apr. 23, 1940 Rogofi Jan. 26,1943 Birkenmaier Sept. 2, 1947 Van Ryan Dec. 16, 1947

